266 BULLETIN UNIVERSITY OF MONTANA 



AS might be supposed, those flowers which depend upon wind polli- 

 nation must produce a great abundance of pollen, even though every de- 

 vice such as light feathered pollen be brought into use. The monoecious 

 rag weed and the pines are good examples of plants which shed their 

 pollen freely. We can readily see how great would be the benefit to a 

 plant if an insect could be induced to carry its pollen. The saving in 

 quantity would be considerable, as well as the advantage before men- 

 tioned of pollination from a distant plant. 



Since there are no one sided bargains in nature the insect must be 

 enticed and paid for his trouble. This involves the necessity of the 

 plant's putting up some kind of a free lunch in the shape of nectar, as in 

 the clover, or edible pollen as in the rose. In the Spiderwort we have 

 some fine hairs growing from the stamens which must make delicious 

 fodder for some of the bees, judging by the way they eat it. Some plants 

 offer lodging for the night and protection from storm and cold. What 

 more could a vagrant insect ask? 



The fact that this free lunch is offered must be advertised, either 

 by an odor to entice the hungry insect or by a showy blossom. Some 

 plants with small inconspicuous blossoms, as in the clover, unite into 

 heads so the busy bee can readily go from one to another without loss of 

 his valuable time, for the summer is short. 



One can follow out this idea almost indefinitely. Plants blooming 

 at night have white flowers because they can thus be more clearly seen 

 by their nocturnal visitors. They are also more likely to be fragrant. 

 Flowers desiring nocturnal visitors are likely to be closed the rest of the 

 day. Flowers that are open for business only a very short time, as the 

 morning glory, have not only showy flowers but delicate stripes of color 

 running from all sides down to the nectaries, seemingly to direct the 

 insect to the sweets with as little loss of time as possible. These nectary 

 guides, as they are called, are very conspicuous in many insect fertilized 

 flowers.^ By following these guides, the welcome host will always rub 

 against the essential organs of the flower and thereby assist in pollination, 

 or in other ways pay for his sup of nectar. 



It may be interesting here to note that the early botanists thought 

 nectar was a waste product that must be removed, and an early sug- 

 gested reason for insect visits was to assist the flower in its removal. 



While most insect-fertilized flowers are beautifully colored and many 

 of them pleasantly scented there are also some that are flesh-colored. 

 They have a bad odor, as the smell of decaying meat. The visits of 

 carrion flies suggest the purpose of the bad odor. 



Sir John Lubbock made an interesting series of experiments from 

 which he dedviced the facts that dull yellow, brownish or purple flowers 

 seem to attract flies more especially. Also that bees and butterflies 

 are more likely to go to violet, red or blue flowers. Packard believes 

 that no insect can distinguish clearly color or objects at a greater dis- 

 tance than six feet. Wliat extremely short sighted animals they are! 

 We know that odors will attract flies from much greater distance. 



The insects, as well as the flowers, are modified to meet the conditions 

 that arise from this inter-dependence. When Darwin's book was under 



